Compliant seals for solid oxide fuel cell stack

Abstract

A seal assembly for a solid oxide fuel cell stack, includes at least two fuel cell stack components having opposed surfaces and a seal member disposed between the surfaces, wherein the seal member is a compliant seal member that is mechanically compliant in both in-plane and out-of-plane directions relative to the surfaces. The seal member is advantageously formed of one or more substantially continuous fibers. Further, preferred materials for the seal member are provided which advantageously allow for a desired level of impermeability while preventing contamination of the fuel cell stack.

1. A seal assembly for a solid oxide fuel cell stack, comprising:
 at least two fuel cells each comprising an electrolyte having a cathode layer on one side and an anode layer on the other side, and at least one bipolar plate between the at least two fuel cells, the at least two fuel cells and the bipolar plate collectively defining at least two fuel cell components having opposed surfaces; and 
 a continuous fiber tow wrapped into a closed-loop structure forming a substantially gas impermeable seal between said opposed surfaces. 
 
     
     
       2. The apparatus according to  claim 1 , wherein said seal comprises a stable oxide ceramic. 
     
     
       3. The apparatus according to  claim 1 , wherein said seal comprises at least one material selected from the group consisting of alumina, magnesia, zirconia, mullite, yttrium aluminum garnate, magnesium silicate and combinations thereof. 
     
     
       4. The apparatus of  claim 1 , wherein said seal is impregnated with at least one metal selected from the group consisting of Ni, Cr, Ag, Cu, Fe, Al and combinations thereof. 
     
     
       5. The apparatus of  claim 1 , wherein said seal is impregnated with at least one material selected from the group consisting of alumina, zirconia, yttria aluminum garnate, magnesium silicate and combinations thereof. 
     
     
       6. The apparatus of  claim 1 , wherein said seal is impregnated with Ag 2 O. 
     
     
       7. The apparatus of  claim 1 , wherein said seal comprises at least a first fiber in a substantially concentric relationship with a second fiber. 
     
     
       8. The apparatus of  claim 7 , wherein said at least two fuel cell components comprise a separator plate and a fuel cell with said seal disposed therebetween. 
     
     
       9. The apparatus of  claim 1 , further comprising a compression stop extending from at least one of said fuel cell components toward the other of said fuel cell components and defining thereon at least one of said opposed surfaces and having a groove for receiving said seal member. 
     
     
       10. The apparatus of  claim 9 , wherein said seal has a height and said groove has a depth, and wherein said height is greater than said depth whereby said seal in said groove can be compressed between said opposed surfaces. 
     
     
       11. A seal assembly for a solid oxide fuel cell stack, comprising:
 at least two fuel cell components having opposed surfaces; and 
 a seal member disposed between said surfaces, wherein said seal member comprises one or more substantially continuous fibers, and wherein said fibers are impregnated with Ag 2 O. 
 
     
     
       12. A seal assembly for a solid oxide fuel cell stack, comprising:
 at least two fuel cells each comprising an electrolyte having a cathode layer on one side and an anode layer on the other side, and at least one bipolar plate between the at least two fuel cells, the at least two fuel cells and the bipolar plate collectively defining at least two fuel cell components having opposed surfaces; 
 a continuous fiber tow wrapped into a closed-loop structure forming a substantially gas impermeable seal between said opposed surfaces; and 
 a compression stop disposed between said opposed surfaces of said fuel cell stack components. 
 
     
     
       13. The apparatus of  claim 12 , further comprising a frame situated between said opposed surfaces, wherein said frame is located adjacent one opposed surface, and wherein said compression stop is disposed on said frame. 
     
     
       14. The apparatus of  claim 12 , wherein said opposed surfaces comprise substantially planar surfaces, and wherein said compression stop extends from one of said substantially planar surfaces toward the other of said substantially planar surfaces.